Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D1/00—Processes for applying liquids or other fluent materials
  • B05D1/28—Processes for applying liquids or other fluent materials performed by transfer from the surfaces of elements carrying the liquid or other fluent material, e.g. brushes, pads, rollers
  • B05D1/286—Processes for applying liquids or other fluent materials performed by transfer from the surfaces of elements carrying the liquid or other fluent material, e.g. brushes, pads, rollers using a temporary backing to which the coating has been applied
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
  • B05D7/50—Multilayers
  • B05D7/52—Two layers
  • B05D7/54—No clear coat specified
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F259/00—Macromolecular compounds obtained by polymerising monomers on to polymers of halogen containing monomers as defined in group C08F14/00
  • C08F259/02—Macromolecular compounds obtained by polymerising monomers on to polymers of halogen containing monomers as defined in group C08F14/00 on to polymers containing chlorine
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F287/00—Macromolecular compounds obtained by polymerising monomers on to block polymers
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/10—Adhesives in the form of films or foils without carriers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
  • B05D7/14—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J2433/00—Presence of (meth)acrylic polymer
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T156/00—Adhesive bonding and miscellaneous chemical manufacture
  • Y10T156/10—Methods of surface bonding and/or assembly therefor
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T156/00—Adhesive bonding and miscellaneous chemical manufacture
  • Y10T156/10—Methods of surface bonding and/or assembly therefor
  • Y10T156/1052—Methods of surface bonding and/or assembly therefor with cutting, punching, tearing or severing
  • Y10T156/1062—Prior to assembly

Definitions

• the present invention relates to a method for the corrosion control treatment of metal surfaces, having the features of the preamble of claim 1 , and also to the use of a self-adhesive for the corrosion control treatment of metal surfaces.
• Metal components are used in a diversity of sectors. They are exposed therein to any of a very wide variety of weathering conditions, and so often a corrosion control treatment is necessary. For this purpose, especially for full-area application of a corrosion control layer to metal components, a variety of methods are known.
• DE 10 2006 006 910 B3 discloses a method in which a corrosion control layer in the form of a zinc lamellae coating is applied to the metal surfaces that are to be protected. The zinc lamellae coating is applied by means of a dipping or spraying method.
• a corrosion control treatment is effected by immersion of the metal surfaces into a cathodically depositable electrocoat material (DE 10 2005 059 314 A1),
• a feature common to the two abovementioned methods is that the corrosion control layer is applied over a relatively large area, more particularly the full area, of the metal surface to be treated.
• a precision seam seal is applied manually or by means of a robot.
• Material used for the precision seam is typically pumpable PVC.
• This pumpable PVC is applied locally to the metal surface, by spraying, and then spread smoothly by means of a brush.
• this method which is fundamentally suitable for edges and transitions, it is difficult to produce the precision seam in the optical quality that is needed in vehicle construction. Instead, the surface often remains rough, and an uneven application is visible to the naked eye.
• the problem on which the present invention is based is that of specifying a method for the corrosion control treatment of metal surfaces that can be carried out without great cost and complexity and that can also be used in particular for protecting edges and transitions of metal components.
• the self-adhesive tape is applied to the respective metal surface and subsequently heated.
• the self-adhesive tape comprises at least one layer of the invention which melts as a result of heating—that is, on heating, it spreads over the metal surface and in so doing forms a continuous corrosion control layer.
• the adhesive tape is self-adhesive and ultimately forms the corrosion control layer, the application can take place very simply, in particular at edges and transitions between different metal components as well.
• the tackiness of the adhesive tape allows preliminary fixing before the corrosion control layer is formed by the heating.
• the self-adhesive tape can be applied uniformly even to small areas, something which with conventional methods, such as the sprayed application of paint, for example, is possible only with difficulty and using further assistants, such as temporary protective films.
• the corrosion control layer is formed with a substantially smooth surface—in other words, to a viewer, the surface of the corrosion control layer is of even and planar form.
• the self-adhesive tape comprises at least one layer of the invention, based on polyacrylates and/or polymethacrylates, which per se is self-adhesive and/or heat-activatable and is therefore suitable for forming the corrosion control layer.
• heat-activatable pressure-sensitive adhesives based on poly(meth)acrylate are used.
• the heat-activatable material advantageously comprises a polymer which comprises
• acrylic monomers comprising acrylic and methacrylic esters with alkyl groups consisting of 1 to 14 C atoms.
• Specific examples are methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, n-butyl acrylate, n-butyl methacrylate, n-pentyl acrylate, n-hexyl acrylate, n-hexyl methacrylate, n-heptyl acrylate, n-octyl acrylate, n-nonyl acrylate, lauryl acrylate, stearyl acrylate, stearyl methacrylate, behenyl acrylate, and the branched isomers thereof, such as 2-ethylhexyl acrylate, for
• R 1 is H and/or CH 3 and the radical —OR 2 is a functional group or comprises a functional group which supports subsequent thermal and/or UV and/or electron-beam crosslinking of the adhesive.
• component (a2) are hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, allyl alcohol, maleic anhydride, itaconic anhydride, itaconic acid, acrylamide and glycidyl methacrylate, benzyl acrylate, benzyl methacrylate, phenyl acrylate, phenyl methacrylate, tert-butylphenyl acrylate, tert-butylphenyl methacrylate, phenoxyethyl acrylate, phenoxyethyl methacrylate, 2-butoxyethyl methacrylate, 2-butoxyethyl acrylate, dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, diethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethyla
• component (a2) are aromatic vinyl compounds, where the aromatic rings consist preferably of C4 to C18 units and may also contain heteroatoms.
• aromatic vinyl compounds where the aromatic rings consist preferably of C4 to C18 units and may also contain heteroatoms.
• Particularly preferred examples are styrene, 4-vinylpyridine, N-vinylphthalimide, methylstyrene, 3,4-dimethoxystyrene, 4-vinylbenzoic acid, this enumeration not being conclusive.
• the monomers are selected such that the resultant polymers can be used as heat-activatable pressure-sensitive adhesives, more particularly such that the resulting polymers have pressure-sensitive adhesion properties in line with the “Handbook of Pressure Sensitive Adhesive Technology” by Donatas Satas (van Nostrand, New York 1989).
• the static glass transition temperature of the resulting polymers is situated advantageously above 30° C.
• the monomers are very preferably selected, and the quantitative composition of the monomer mixture advantageously selected, such as to give the desired T g,A value for the polymer in accordance with the Fox equation (E1) (cf. T. G. Fox, Bull. Am. Phys. Soc. 1956, 1, 123).
• n represents the serial number of the monomers used
• W n the mass fraction of the respective monomer n (% by weight)
• T g,n the respective glass transition temperature of the homopolymer of the respective monomer n in K.
• the polymer may be treated by plasma or corona prior to coating.
• plasma treatment for example, apparatus from the company Plasmatreat is suitable.
• a polyacrylate pressure-sensitive adhesive which comprises a polymer which in respect of the polymer comprises
• acrylic monomers comprising acrylic and methacrylic esters with alkyl groups consisting of 4 to 14 C atoms, preferably 4 to 9 C atoms.
• alkyl groups consisting of 4 to 14 C atoms, preferably 4 to 9 C atoms.
• Specific examples are n-butyl acrylate, n-pentyl acrylate, n-hexyl acrylate, n-heptyl acrylate, n-octyl acrylate, n-nonyl acrylate, lauryl acrylate, stearyl acrylate, behenyl acrylate, and the branched isomers thereof, such as 2-ethylhexyl acrylate, for example.
• Further classes of compound for use which may likewise be added in small amounts under (b1), are methyl methacrylates, cyclohexyl methacrylates, isobornyl acrylate, and isobornyl methacrylates.
• the monomers (b2) used with greater preference for the monomers (b2) are vinyl esters, vinyl ethers, vinyl halides, vinylidene halides, vinyl compounds with aromatic rings and heterocycles in a position.
• vinyl esters, vinyl ethers, vinyl halides, vinylidene halides, vinyl compounds with aromatic rings and heterocycles in a position a number of non-restricting examples may be given: vinyl acetate, vinyl formamide, vinylpyridine, ethyl vinyl ether, vinyl chloride, vinylidene chloride, and acrylonitrile.
• monomers (b2) particular preference is given to using monomers having the following functional groups: hydroxyl, carboxyl, epoxy, acid-amide, isocyanato or amino groups.
• R 1 is H or CH 3 and the radical —OR 2 is or comprises a functional group which allows subsequent thermal, UV and/or electron-beam crosslinking of the pressure-sensitive adhesive.
• component (b2) are hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, allyl alcohol, maleic anhydride, itaconic anhydride, itaconic acid, acrylamide and glycidyl methacrylate, benzyl acrylate, benzyl methacrylate, phenyl acrylate, phenyl methacrylate, tert-butylphenyl acrylate, tert-butylphenyl methacrylate, phenoxyethyl acrylate, phenoxyethyl methacrylate, 2-butoxyethyl methacrylate, 2-butoxyethyl acrylate, dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, diethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethyla
• aromatic vinyl compounds are used, where the aromatic rings consist preferably of C4 to C18 units and may also contain heteroatoms.
• Particularly preferred examples are styrene, 4-vinylpyridine, N-vinylphthalimide, methylstyrene, 3,4-dimethoxystyrene, 4-vinylbenzoic acid, this enumeration not being conclusive.
• the monomers are selected such that the resultant polymers can be used as industrially applicable pressure-sensitive adhesives, more particularly such that the resulting polymers have pressure-sensitive adhesion properties in line with the “Handbook of Pressure Sensitive Adhesive Technology” by Donatas Sates (van Nostrand, New York 1989).
• the desired glass transition temperature can be controlled through the application of the Fox equation (E1) in the context of the compilation of the monomer mixture on which the polymerization is based.
• the static glass transition temperature of the resulting polymer is advantageously below 15° C.
• free-radical sources are peroxides, hydroperoxides, and azo compounds.
• Some nonlimiting examples of typical free-radical initiators that may be mentioned here include potassium peroxodisulfate, dibenzoyl peroxide, cumene hydroperoxide, cyclohexanone peroxide, di-tert-butyl peroxide, azodiisobutyronitrile, cyclohexylsulfonyl acetyl peroxide, diisopropyl percarbonate, tert-butyl peroctoate, and benzpinacol.
• a particularly preferred free-radical initiator used is 1,1′-azobis(cyclohexanecarbonitrile) (Vazo 88® from DuPont).
• the average molecular weights M n of the pressure-sensitive adhesives (PSAs) formed in the free-radical polymerization are very preferably selected such that they are situated within a range from 20 000 to 2 000 000 g/mol; specifically for further use as pressure-sensitive hotmelts, PSAs having average molecular weights M n of 100 000 to 500 000 g/mol are prepared.
• the average molecular weight is determined via size exclusion chromatography (SEC) or matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS).
• the polymerization may be carried out in bulk, in the presence of one or more organic solvents, in the presence of water, or in mixtures of organic solvents and water.
• Suitable organic solvents are pure alkanes (for example, hexane, heptane, octane, isooctane), aromatic hydrocarbons (for example, benzene, toluene, xylene), esters (for example, ethyl acetate, propyl, butyl or hexyl acetate), halogenated hydrocarbons (for example, chlorobenzene), alkanols (for example, methanol, ethanol, ethylene glycol, ethylene glycol monomethyl ether), and ethers (for example, diethyl ether, dibutyl ether) or mixtures thereof.
• the aqueous polymerization reactions may be admixed with a water-miscible or hydrophilic co-solvent, in order to ensure that the reaction mixture is present in the form of a homogeneous phase during monomer conversion.
• Co-solvents which can be used with advantage for the present invention are selected from the following group, consisting of aliphatic alcohols, glycols, ethers, glycol ethers, pyrrolidines, N-alkylpyrrolidinones, N-alkylpyrrolidones, polyethylene glycols, polypropylene glycols, amides, carboxylic acids and salts thereof, esters, organic sulfides, sulfoxides, sulfones, alcohol derivatives, hydroxy ether derivatives, amino alcohols, ketones and the like, and also derivatives and mixtures thereof.
• the polymerization time is between 4 and 72 hours.
• the introduction of heat is essential to initiate the polymerization.
• the polymerization may be initiated by heating to 50 to 160° C., depending on initiator type.
• nitroxides such as, for example 2,2,5,5-tetramethyl-1-pyrrolidinyloxyl (PROXYL), 3-carbamoyl-PROXYL, 2,2-dimethyl-4,5-cyclohexyl-PROXYL, 3-oxo-PROXYL, 3-hydroxylimine-PROXYL, 3-aminomethyl-PROXYL, 3-methoxy-PROXYL, 3-tert-butyl-PROXYL, 3,4-di-tert-butyl-PROXYL—2,2,6,6-tetramethyl-1-piperidinyloxyl pyrrolidinyloxyl (TEMPO), 4-benzoyloxy-TEMPO, 4-methoxy-TEMPO, 4-chloro-TEMPO, 4-hydroxy-TEMPO, 4-oxo-TEMPO, 4-amino-TEMPO, 2,2,6,6-tetraethyl-1-piperidinyloxyloxy
• TEMPO 2,2,5,5-tetramethyl
• U.S. Pat. No. 4,581,429 A discloses a controlled-growth free-radical polymerization process which employs as its initiator a compound of the formula R′R′′N—O—Y, in which Y is a free radical species which is able to polymerize unsaturated monomers.
• the reactions however, in general have low conversion rates.
• a particular problem is the polymerization of acrylates, which takes place only to very low yields and molar masses.
• WO 98/13392 A1 describes open-chain alkoxyamine compounds which have a symmetrical substitution pattern.
• EP 735 052 A1 discloses a process for preparing thermoplastic elastomers having narrow molar mass distributions.
• WO 96/24620 A1 describes a polymerization process in which very specific free-radical compounds are used, such as, for example, phosphorus-containing nitroxides based on imidazolidine.
• WO 98/44008 A1 discloses specific nitroxyls based on morpholines, piperazinones, and piperazinediones.
• DE 199 49 352 A1 describes heterocyclic alkoxyamines as regulators in controlled-growth free-radical polymerizations.
• ATRP Atom Transfer Radical Polymerization
• the initiator used comprising preferably monofunctional or difunctional secondary or tertiary halides and the halide or halides being abstracted using complexes of Cu, Ni, Fe, Pd, Pt, Ru, Os, Rh, Co, Ir, Ag or Au (EP 0 824 111 A1; EP 826 698 A1; EP 824 110 A1; EP 841 346 A1; EP 850 957 A1).
• ATRP Atom Transfer Radical Polymerization
• the polymer used in accordance with the invention can be prepared advantageously via an anionic polymerization.
• reaction medium it is preferred to use inert solvents, such as aliphatic and cycloaliphatic hydrocarbons, for example, or else aromatic hydrocarbons.
• the living polymer is represented generally by the structure PL(A)-Me, where Me is a metal from Group I of the Periodic Table, such as lithium, sodium or potassium, for example, and PL(A) is a growing polymer block of the monomers A.
• Me is a metal from Group I of the Periodic Table, such as lithium, sodium or potassium, for example
• PL(A) is a growing polymer block of the monomers A.
• the molar mass of the polymer under preparation is dictated by the ratio of initiator concentration to monomer concentration.
• Suitable polymerization initiators include n-propyllithium, n-butyllithium, sec-butyllithium, 2-naphthyllithium, cyclohexyllithium or octyllithium, this enumeration making no claim to completeness. Furthermore, initiators based on samarium complexes are known for the polymerization of acrylates ( Macromolecules 1995, 28, 7886) and can be used here.
• difunctional initiators such as, for example, 1,1,4,4-tetraphenyl-1,4-dilithiobutane or 1,1,4,4-tetraphenyl-1,4-dilithioisobutane.
• Co-initiators may likewise be employed. Suitable co-initiators include lithium halides, alkali metal alkoxides or alkylaluminum compounds.
• the ligands and co-initiators are selected such that acrylate monomers, such as n-butyl acrylate and 2-ethylhexyl acrylate, for example, can be polymerized directly and do not have to be generated in the polymer by transesterification with the corresponding alcohol.
• RAFT polymerization reversible addition-fragmentation chain transfer polymerization
• the polymerization procedure is described comprehensively in specifications WO 98/01478 A1 and WO 99/31144 A1, for example.
• Particularly advantageously suitable for the preparation are trithiocarbonates of the general structure R′′′—S—C(S)—S—R′′′ ( Macromolecules 2000, 33, 243-245).
• the trithiocarbonates (TTC1) and (TTC2) or the thio compounds (THI1) and (THI2) are used for the polymerization, where ⁇ is a phenyl ring which may be unfunctionalized or functionalized by alkyl or aryl substituents which are linked directly or via ester or ether bridges; a cyano group; or a saturated or unsaturated aliphatic radical.
• the phenyl ring ⁇ may optionally carry one or more polymer blocks, examples being polybutadiene, polyisoprene, polychloroprene or poly(meth)acrylate, which may be constructed in line with the definition for P(A) or P(B), or polystyrene, to name but a few.
• Functionalizations may be, for example, halogens, hydroxyl groups, epoxide groups, groups containing nitrogen or groups containing sulfur, without this enumeration making any claim to completeness.
• initiator systems are preferred which further comprise additional free-radical initiators for the polymerization, more particularly thermally decomposing, free-radical-forming azo or peroxo initiators.
• additional free-radical initiators for the polymerization more particularly thermally decomposing, free-radical-forming azo or peroxo initiators.
• Suitable in principle for this purpose are all of the customary initiators known for acrylates.
• the production of C-centered free radicals is described in Houben-Weyl, Methoden der Organischen Chemie, Vol. E 19a, p. 60ff. These methods are preferentially employed.
• free-radical sources are peroxides, hydroperoxides, and azo compounds.
• a number of nonexclusive examples of typical free-radical initiators that may be mentioned here include the following: potassium peroxodisulfate, dibenzoyl peroxide, cumene hydroperoxide, cyclohexanone peroxide, cyclohexylsulfonyl acetyl peroxide, di-tert-butyl peroxide, azodiisobutyronitrile, diisopropyl percarbonate, tert-butyl peroctoate, benzpinacol.
• One very preferred variant uses, as free-radical initiator, 1,1′-azobis(cyclohexylnitrile) (Vazo 88®, DuPont) or 2,2-azobis(2-methylbutanednitrile) (Vazo 67®, DuPont). Furthermore, it is also possible to use free-radical sources which release free radicals only under UV irradiation.
• the PSAs may be admixed with resins.
• Tackifying resins for addition include, without exception, all tackifying resins which are already known and are described in the literature. As representatives, mention may be made of the pinene resins, indene resins, and rosins, their disproportionated, hydrogenated, polymerized, and esterified derivatives and salts, the aliphatic and aromatic hydrocarbon resins, terpene resins and terpene-phenolic resins, and also C 5 , C 9 , and other hydrocarbon resins. Any desired combinations of these and further resins may be used in order to adjust the properties of the resultant adhesive in accordance with requirements.
• plasticizers plasticizing agents
• fillers for example, fibers, carbon black, zinc oxide, titanium dioxide, chalk, solid or hollow glass beads, microbeads made of other materials, silica, silicates
• nucleating agents for example, expandants, compounding agents and/or aging inhibitors, in the form for example of primary and secondary antioxidants or in the form of light stabilizers, to be added.
• the internal strength (cohesion) of the PSA is increased preferably by crosslinking.
• compatible crosslinker substances may optionally be added to the acrylate-containing PSAs.
• suitable crosslinkers include metal chelates, polyfunctional isocyanates, polyfunctional amines, polyfunctional epoxides or polyfunctional alcohols.
• Polyfunctional acrylates as well may be used with advantage as crosslinkers for actinic irradiation.
• polyacrylate materials which are crosslinkable.
• Crosslinking is accomplished preferably in the form of thermal crosslinking, during the melting of the polyacrylate layer of the invention of the self-adhesive tape, which may be self-adhesive and/or heat-activatable. Radiation crosslinking or other crosslinking methods, however, can also be employed.
• the self-adhesive material becomes significantly less susceptible to high temperatures, and so the self-adhesive material is then no longer able to melt.
• the crosslinking in particular, thus allows the use of self-adhesive tapes which per se, on account of their deficient temperature stability, could not be used as a productive component—that is, a component which remains durably.
• Crosslinking may, as described, take place in different ways. On the one hand, crosslinking may take place during or after the melting of the self-adhesive tape, by radiation, not only via UV rays but also with the aid of electron beams.
• Crosslinking by thermal energy in other words during the melting of the acrylate layer of the self-adhesive tape, may take place with polyfunctional isocyanates, polyfunctional epoxides, polyfunctional amines, and polyfunctional alcohols, and further thermal crosslinkers known to the skilled person.
• EP 1 001 893 B1 and EP 13734425 B1 cite examples of such thermal crosslinking during the above-stated applications, and also cite reactive systems such as, cyanoacrylates for example—these, however, have the drawback that the adhesive tapes can be stored only at low temperatures without losing effectiveness, and must be first heated again in turn for application, in order that the adhesive tapes remain adhering to the substrate.
• urea derivatives which have at least two urea functionalities and also undergo thermal decomposition at the melting temperature or in the region of the melting temperature, releasing an isocyanate and an amine.
• the amine which functions as a blocking agent for the isocyanate, surprisingly also possesses the capacity to react as an accelerator for the epoxide crosslinking, without the epoxide not reacting with the polyacrylate.
• the self-adhesive tape with the polyacrylate layer of the invention is storage-stable, and there is no crosslinking reaction.
• urea derivatives of the invention of this kind is the Dyhard® UR 500 from EVONIK.
• Substances containing epoxide groups that are used are, in particular, polyfunctional epoxides, in other words those which have at least two epoxide units per molecule (i.e., are at least difunctional). These compounds may be aromatic compounds and aliphatic compounds.
• polyfunctional epoxides are oligomers of epichlorohydrin, epoxy ethers of polyhydric alcohols [more particularly ethylene, propylene, and butylene glycols, polyglycols, thiodiglycols, glycerol, pentaerythritol, sorbitol, polyvinyl alcohol, polyallyl alcohol, and the like], epoxy ethers of polyhydric phenols [more particularly resorcinol, hydroquinone, bis(4-hydroxyphenyl)methane, bis(4-hydroxy-3-methylphenyl)methane, bis(4-hydroxy-3,5-dibromophenyl)methane, bis(4-hydroxy-3,5-difluorophenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-
• Very suitable ethers are, for example, 1,4-butanediol diglycidyl ether, polyglycerol-3 glycidyl ether, cyclohexanedimethanol diglycidyl ether, glycerol triglycidyl ether, neopentylglycol diglycidyl ether, pentaerythritol tetraglycidyl ether, 1,6-hexanediol diglycidyl ether), polypropylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether, bisphenol A diglycidyl ether, and bisphenol F diglycidyl ether.
• epoxidized cyclohexene derivatives with a functionality of at least two, such as, for example, UVACURE® 1500 from CYTEC 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate and bis-3,4-epoxy-cyclohexylmethyl adipate.
• the pressure-sensitive adhesiveness of the self-adhesive material may be generated optionally by thermal activation or by solvent activation.
• Particularly preferred are self-adhesive polyacrylates or the coating of the purely heat-activatable polyacrylate layer with a pressure-sensitive adhesive, more preferably a polyacrylate PSA, it being possible here to use any of the kinds of PSAs that are familiar to the skilled person, and the adhesives, if desired, are anchored by means of a primer or a physical pretreatment on the purely heat-activatable polyacrylate layer.
• the adhesive tape is preferably provided on at least one side with a liner, in other words, for example, a silicone-coated film or silicone paper.
• a further advantageous embodiment of the invention is the use of a carrier-free adhesive for the self-adhesive tape.
• a carrier-free adhesive is an adhesive which does not have a permanent carrier, such as a polymer film or a nonwoven.
• the self-adhesive material is applied solely to a liner, in other words to a material which serves only temporarily for the support and greater ease of applicability of the self-adhesive material. After the application of the self-adhesive material to the metal surface, the liner is then removed. In contrast to the layer of the invention, in this case the self-adhesive material, therefore, the liner does not constitute a productive component.
• the carrier-free adhesive that then remains can be melted particularly easily without adverse effects anticipated from a carrier material.
• the layer of the invention can be prepared from solution and also from the melt.
• suitable preparation procedures encompass not only batch processes but also continuous processes.
• Particularly preferred is the continuous manufacture by means of an extruder, with subsequent coating directly on a liner with or without layer of adhesive.
• any subsequent plastisol layer or paint layer it may be modified.
• modification are physical treatments with corona discharge or plasma, coating with adhesion-promoting substances such as hydrogenated nitrile rubber, vinylidene chloride polymer or adhesion promoters of the kind known to the skilled person for the priming of plastics parts made of polyolefins (for example, automobile fenders) for subsequent paint finishes.
• the surface for this purpose may also be with a film such as, for example, acrylonitrile-butadiene-styrene copolymer (ABS), caprolactam, cellophane, ethylene-vinyl acetate copolymer (EVA), Kapton, polyester (PEN, PET), polyolefin (PE, PP, etc), polyacrylate (PMMA, etc.), polyamide, polyimide, polystyrene, polyvinyl chloride or polyurethane.
• ABS acrylonitrile-butadiene-styrene copolymer
• EVA ethylene-vinyl acetate copolymer
• Kapton Kapton
• polyester PET
• PET polyolefin
• PE polyolefin
• PMMA polyacrylate
• polyamide polyimide
• polystyrene polyvinyl chloride or polyurethane.
• a barrier layer is useful in order to prevent migration of plasticizer from the plastisol layer into the corrosion control layer, or migration of plasticizer from the corrosion control layer into a paint layer. Additionally, this layer may result in improved paintability, and also serve as a barrier against gases that emerge from the joints in the painting operation.
• This may be, for example, a coating with vinylidene chloride polymer or application of a film such as, for example, acrylonitrile-butadiene-styrene copolymer (ABS), caprolactam, cellophane, ethylene-vinyl acetate copolymer (EVA), Kapton, polyester (PEN, PET), polyolefin (PE, PP, etc.), polyacrylate (PMMA, etc.), polyamide, polyimide, polystyrene, polyvinyl chloride or polyurethane.
• ABS acrylonitrile-butadiene-styrene copolymer
• EVA ethylene-vinyl acetate copolymer
• PEN polyester
• PET polyolefin
• PMMA polyacrylate
• polyamide polyimide
• polystyrene polyvinyl chloride or polyurethane.
• the melting of the layer of the invention and also the start of the thermal crosslinking by the deblocking of the crosslinker and also the release of the accelerant ought to take place only at not less than 90° C., preferably at not less than 110° C., more preferably at not less than 130° C.
• the minimum temperature required in each case is determined by the specific composition of the self-adhesive material.
• This temperature ought on the one hand to be selected as high as possible, in order to provide the self-adhesive material with the maximum storage stability; on the other hand, however, the temperature ought not to be too high, in order that the melting and crosslinking can be carried out in as energy-optimized manner as possible and also that further components used, for example, in a motor vehicle body are not subjected to excessively high temperatures.
• a temperature of not more than 200° C., preferably of not more than 180° C., more preferably of not more than 160° C. has been found appropriate for the melting of the self-adhesive material.
• the layer of the invention ought to be applied to the metal surface with a layer thickness of least 50 ⁇ m, preferably of at least 100 ⁇ m, more preferably of at least 200 ⁇ m. Moreover, the layer thickness ought to be not more than 750 ⁇ m, preferably not more than 600 ⁇ m, more preferably not more than 400 ⁇ m. The selection of such a layer thickness ensures that, on the one hand, the metal surface is sufficiently covered during the melting and crosslinking of the self-adhesive material, while on the other hand the thickness of the corrosion control layer does not become too great.
• the self-adhesive composition is first wound onto a roll and is applied from this roll to the metal surface. The worker can then separate off the self-adhesive material in the required length.
• the self-adhesive material In order to allow the self-adhesive material to be wound onto a roll, it is typically covered on one side with a liner.
• the liner enables easy unwind of the self-adhesive material from the roll, and thereby facilitates handling.
• presentation in the form of diecut parts may also be of advantage.
• the desired shapes are diecut from the adhesive tape, and typically applied to a liner. This construction may then be processed either into a roll or into individual sheets. It is immaterial here whether diecuts of different or equal shape are assembled on a liner.
• the present invention provides, furthermore, for the use of a self-adhesive tape with the polyacrylate layer of the invention for the corrosion control treatment of metal surfaces.
• the self-adhesive material is selected and embodied in particular in accordance with the features described above.
• the adhesive after melting has taken place ought to have a very high temperature resistance, in order to allow as diverse applications as possible for the corrosion-control-treated metal surfaces. Provision is made in particular for the adhesive, after melting has taken place, to be temperature-resistant to ⁇ 5° C., preferably to ⁇ 15° C., more preferably to ⁇ 30° C.
• the adhesive after melting has taken place ought also to be temperature-resistant to 70° C., preferably to 80° C., more preferably to 100° C.
• adheresive tape for the purposes of this invention encompasses all sheetlike structures such as two-dimensionally extended films or film sections, tapes with extended length and limited width, tape sections and the like, and lastly also diecuts or labels.
• the metal panels were subsequently subjected to different ambient conditions.
• the temperature was varied in alternation between about ⁇ 5° C. and 70° C.
• the elasticity of the original polyacrylate material remained largely retained, with a reduced risk, consequently, of delamination of the corrosion control layer.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Wood Science & Technology (AREA)
• Adhesives Or Adhesive Processes (AREA)
• Adhesive Tapes (AREA)
• Preventing Corrosion Or Incrustation Of Metals (AREA)

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• 2009
  • 2009-01-29 DE DE102009006593A patent/DE102009006593A1/de not_active Withdrawn
• 2010
  • 2010-01-06 JP JP2011546730A patent/JP2012516387A/ja not_active Withdrawn
  • 2010-01-06 US US13/146,458 patent/US8574392B2/en active Active
  • 2010-01-06 WO PCT/EP2010/050072 patent/WO2010086196A1/fr active Application Filing
  • 2010-01-06 EP EP10700967.2A patent/EP2391672B2/fr active Active
  • 2010-01-06 MX MX2011007538A patent/MX2011007538A/es active IP Right Grant
  • 2010-01-06 ES ES10700967T patent/ES2401050T3/es active Active
  • 2010-01-06 CN CN201080011692XA patent/CN102348744B/zh active Active
  • 2010-01-06 KR KR1020117020095A patent/KR101598106B1/ko active IP Right Grant

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